Changes in vegetation seasonality and livestock stocking rate in La Pampa Province (Argentina)

Crop production is traversing expansion and intensification processes all over the planet and in consequence the large scale cattle production is being displaced to marginal lands with lower stocking capacity. The objective of this work was to assess the seasonality of vegetation in La Pampa province located in a semiarid region in Argentina and to explore if the variations in seasonality are related to the stocking rate. The hypothesis is the changes in stocking rate of rangelands and its grazing pressure alter the proportion of different vegetation functional groups and so the vegetation seasonality. It is predicted that overgrazing of seasonal grasses will alter the proportion of woody species having consequences over spectral indices. It was analyzed satellite data, particularly the MODIS Enhanced Vegetation Index (EVI) and related it to stocking rate records from SENASA. This work evidences the relationship between the stocking rate and the spectral index EVI, indicator of the primary productivity of vegetation, at departmental scale in the natural areas of Monte and Espinal of La Pampa. Results indicate that in western region (Monte) there was an increment in the stocking rate at department level and a decrease in vegetation seasonality. It is posed that the higher grazing pressure led to the overgrazing of the most palatable herbaceous species, increasing the shrub proportion in landscape.Crop production is traversing expansion and intensification processes all over the planet and in consequence the large scale cattle production is being displaced to marginal lands with lower stocking capacity. The objective of this work was to assess the seasonality of vegetation in La Pampa province located in a semiarid region in Argentina and to explore if the variations in seasonality are related to the stocking rate. The hypothesis is the changes in stocking rate of rangelands and its grazing pressure alter the proportion of different vegetation functional groups and so the vegetation seasonality. It is predicted that overgrazing of seasonal grasses will alter the proportion of woody species having consequences over spectral indices. It was analyzed satellite data, particularly the MODIS Enhanced Vegetation Index (EVI) and related it to stocking rate records from SENASA. This work evidences the relationship between the stocking rate and the spectral index EVI, indicator of the primary productivity of vegetation, at departmental scale in the natural areas of Monte and Espinal of La Pampa. Results indicate that in western region (Monte) there was an increment in the stocking rate at department level and a decrease in vegetation seasonality. It is posed that the higher grazing pressure led to the overgrazing of the most palatable herbaceous species, increasing the shrub proportion in landscape

Changes in vegetation seasonality and livestock stocking rate in La Pampa Province (Argentina)

Fil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.Fil: Di Bella, Carlos Marcelo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información. Buenos Aires, Argentina.Fil: Di Bella, Carlos Marcelo. CONICET. Buenos Aires, Argentina.Fil: Beget, María Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.Fil: Campos, Alfredo Nicolás. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.Fil: Campos, Alfredo Nicolás. Universidad Tecnológica Nacional (UTN). Facultad Regional Buenos Aires. Departamento de Electrónica. Buenos Aires, Argentina.Fil: Viglizzo, Ernesto F. CONICET. San Luis, Argentina.Fil: Viglizzo, Ernesto F. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro Regional La Pampa – San Luis. San Luis, Argentina.Fil: Jobbágy, Esteban G. Universidad de San Luis. Grupo de Estudios Ambientales. San Luis, Argentina.Fil: Jobbágy, Esteban G. CONICET - Universidad de San Luis. Grupo de Estudios Ambientales. San Luis, Argentina.Fil: García, Alfredo Gabriel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.Fil: García, Alfredo Gabriel. CONICET. Buenos Aires, Argentina.Fil: Sycz, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.Fil: Cotroneo, Santiago Miguel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos (INTA-CIRN). Hurlingham, Buenos Aires, Argentina.La producción de cultivos está atravesando procesos de expansión e intensificación alrededor de todo el planeta. En consecuencia, la producción ganadera está siendo desplazada hacia tierras marginales de menor capacidad de carga. El objetivo de este trabajo es evaluar la estacionalidad de la vegetación en la provincia de La Pampa, ubicada en la región semiárida argentina; y explorar si las variaciones en la estacionalidad están relacionadas con la carga de ganado vacuno.Se plantea como hipótesis que los cambios en la carga animal y la presión de pastoreo alteran la proporción de diferentes grupos funcionales de vegetación, y de esta manera, su estacionalidad. Se predice que el sobrepastoreo de los pastos más estacionales alterará la proporción de especies leñosas, y ello repercutirá sobre los índices espectrales. Se analizó la información satelital, particularmente el Índice de Vegetación Mejorado (EVI) de MODIS y se lo relacionó con los registros de carga animal de SENASA. Este trabajo evidencia la relación entre la carga animal y el EVI, indicador de la productividad primaria de la vegetación, a la escala de departamento en las áreas naturales del Monte y el Espinal de La Pampa. Los resultados indican que al oeste de la provincia (Monte) hubo un aumento de la carga animal y una disminución de la estacionalidad de la vegetación a escala de departamento. La mayor presión de pastoreo habría conducido al sobrepastoreo de las especies herbáceas más palatables aumentando la proporción de arbustos en el paisaje.tbls., grafs., mapa

Cambios en la estacionalidad de la vegetación y la carga animal en la provincia de La Pampa (Argentina)

Crop production is traversing expansion and intensification processes all over the planet and in consequence the large scale cattle production is being displaced to marginal lands with lower stocking capacity. The objective of this work was to assess the seasonality of vegetation in La Pampa province located in a semiarid region in Argentina and to explore if the variations in seasonality are related to the stocking rate. The hypothesis is the changes in stocking rate of rangelands and its grazing pressure alter the proportion of different vegetation functional groups and so the vegetation seasonality. It is predicted that overgrazing of seasonal grasses will alter the proportion of woody species having consequences over spectral indices. It was analyzed satellite data, particularly the MODIS Enhanced Vegetation Index (EVI) and related it to stocking rate records from SENASA. This work evidences the relationship between the stocking rate and the spectral index EVI, indicator of the primary productivity of vegetation, at departmental scale in the natural areas of Monte and Espinal of La Pampa. Results indicate that in western region (Monte) there was an increment in the stocking rate at department level and a decrease in vegetation seasonality. It is posed that the higher grazing pressure led to the overgrazing of the most palatable herbaceous species, increasing the shrub proportion in landscape.La producción de cultivos está atravesando procesos de expansión e intensificación alrededor de todo el planeta. En consecuencia, la producción ganadera está siendo desplazada hacia tierras marginales de menor capacidad de carga. El objetivo de este trabajo es evaluar la estacionalidad de la vegetación en la provincia de La Pampa, ubicada en la región semiárida argentina; y explorar si las variaciones en la estacionalidad están relacionadas con la carga de ganado vacuno. Se plantea como hipótesis que los cambios en la carga animal y la presión de pastoreo alteran la proporción de diferentes grupos funcionales de vegetación, y de esta manera, su estacionalidad. Se predice que el sobrepastoreo de los pastos más estacionales alterará la proporción de especies leñosas, y ello repercutirá sobre los índices espectrales. Se analizó la información satelital, particularmente el Índice de Vegetación Mejorado (EVI) de MODIS y se lo relacionó con los registros de carga animal de SENASA. Este trabajo evidencia la relación entre la carga animal y el EVI, indicador de la productividad primaria de la vegetación, a la escala de departamento en las áreas naturales del Monte y el Espinal de La Pampa. Los resultados indican que al oeste de la provincia (Monte) hubo un aumento de la carga animal y una disminución de la estacionalidad de la vegetación a escala de departamento. La mayor presión de pastoreo habría conducido al sobrepastoreo de las especies herbáceas más palatables aumentando la proporción de arbustos en el paisaje.Fil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Beget, María Eugenia. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Campos, Alfredo Nicolás. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Viglizzo, Ernesto. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Jobbágy, Esteban. Consejo Nacional de Investigaciones Científicas y TécnicasFil: García, Alfredo Gabriel. Instituto Nacional de Tecnología Agropecuaria (Argentina)Fil: Cotroneo, Santiago. Instituto Nacional de Tecnología Agropecuaria (Argentina

Changes in vegetation seasonality and livestock stocking rate in La Pampa Province (Argentina) = Cambios en la estacionalidad de la vegetación y la carga animal en la provincia de La Pampa (Argentina)

Crop production is traversing expansion and intensification processes all over the planet and in consequence the large scale cattle production is being displaced to marginal lands with lower stocking capacity. The objective of this work was to assess the seasonality of vegetation in La Pampa province located in a semiarid region in Argentina and to explore if the variations in seasonality are related to the stocking rate. The hypothesis is the changes in stocking rate of rangelands and its grazing pressure alter the proportion of different vegetation functional groups and so the vegetation seasonality. It is predicted that overgrazing of seasonal grasses will alter the proportion of woody species having consequences over spectral indices. It was analyzed satellite data, particularly the MODIS Enhanced Vegetation Index (EVI) and related it to stocking rate records from SENASA. This work evidences the relationship between the stocking rate and the spectral index EVI, indicator of the primary productivity of vegetation, at departmental scale in the natural areas of Monte and Espinal of La Pampa. Results indicate that in western region (Monte) there was an increment in the stocking rate at department level and a decrease in vegetation seasonality. It is posed that the higher grazing pressure led to the overgrazing of the most palatable herbaceous species, increasing the shrub proportion in landscape.La producción de cultivos está atravesando procesos de expansión e intensificación alrededor de todo el planeta. En consecuencia, la producción ganadera está siendo desplazada hacia tierras marginales de menor capacidad de carga. El objetivo de este trabajo es evaluar la estacionalidad de la vegetación en la provincia de La Pampa, ubicada en la región semiárida argentina; y explorar si las variaciones en la estacionalidad están relacionadas con la carga de ganado vacuno. Se plantea como hipótesis que los cambios en la carga animal y la presión de pastoreo alteran la proporción de diferentes grupos funcionales de vegetación, y de esta manera, su estacionalidad. Se predice que el sobrepastoreo de los pastos más estacionales alterará la proporción de especies leñosas, y ello repercutirá sobre los índices espectrales. Se analizó la información satelital, particularmente el Índice de Vegetación Mejorado (EVI) de MODIS y se lo relacionó con los registros de carga animal de SENASA. Este trabajo evidencia la relación entre la carga animal y el EVI, indicador de la productividad primaria de la vegetación, a la escala de departamento en las áreas naturales del Monte y el Espinal de La Pampa. Los resultados indican que al oeste de la provincia (Monte) hubo un aumento de la carga animal y una disminución de la estacionalidad de la vegetación a escala de departamento. La mayor presión de pastoreo habría conducido al sobrepastoreo de las especies herbáceas más palatables aumentando la proporción de arbustos en el paisaje.Instituto de Clima y AguaFil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; ArgentinaFil: Beget, Maria Eugenia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Campos, Alfredo Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Universidad Tecnológica Nacional. Facultad Regional de Buenos Aires. Departamento de Electrónica; ArentinaFil: Viglizzo, Ernesto Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Jobbagy Gampel, Esteban Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis; ArgentinaFil: Garcia, Alfredo Gabriel.Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sycz, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Cotroneo, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentin

Preservación y rehabilitación del monte nativo en el chaco árido argentino: el caso de la asociación de campesinos del Valle del Conlara

En la Región Chaqueña argentina, el bosque nativo aún se pierde por la expulsión de campesinos y su reemplazo por monocultivo, mientras el bosque remanente se degrada por sobrepastoreo. Al sur de esa región, en provincia de San Luis, la “Asociación Campesinos del Valle del Conlara” (ACVC) asume en 2007 la defensa del monte nativo como estrategia fundamental en disputa al modelo del agronegocio. El presente estudio de caso analiza cómo la ACVC contribuyó en un período de 10 años (2007–2017) a la preservación y rehabilitación del monte nativo en sistemas campesinos de la zona. Se analizaron procesos en dos escalas: en la de sociedad local se abordaron las acciones sociales colectivas, y en la predial se analizaron las prácticas de manejo implementadas, sus alcances, limitaciones y efectos sobre la condición de monte. Se realizaron entrevistas semi–estructuradas y talleres con actores locales, y se evaluó la condición del monte mediante bioindicadores de vegetación. La ACVC impulsó campañas de visibilización sobre la importancia del monte, procesos socio–organizativos, formación en educación ambiental e investigación–acción–participativa, que permitieron promover prácticas de manejo a escala predial. Las/os campesinas/os preservan una alta proporción del predio con monte nativo, que descansan del pastoreo durante la estación de crecimiento de la vegetación duplicando su cobertura, posibilitado por la utilización estratégica de verdeos de verano o pasturas. Concluimos que las acciones impulsadas por la ACVC la consolidan como un actor clave en la preservación y rehabilitación del monte nativo en la zona.In the Dry Chaco ecoregion, the native forest is massively cleared without planning at the regional scale, and peasants are being expelled from these lands. In San Luis (Argentina), the peasant organization “Asociación Campesinos del Valle del Conlara” (ACVC) assumed since 2007 the defense of native forests as a fundamental strategy in the dispute with the agribusiness model. The goal of this study case was to analyze how the ACVC contributed in a 10 year period (2007-2017) to the preservation and rehabilitation of the native forest in peasant systems. Two scales were assessed through qualitative and quantitative methodologies: the local society, related to collaborative social actions, and the farm level, related to the management practices, their scope and limitations. Semi–structured interviews and workshops with local actors were carried out and forest condition was evaluated using vegetation bioindicators. The ACVC promoted actions to improve visibility of the importance of the native forest, socio–organizational processes, and management practices aimed at the rehabilitation of degraded forests. Peasants preserve a high proportion of the native vegetation to sustain livestock grazing in the winter dry season. In the summer wet season they use perennial or annual pastures to allow grazing rest. These practices duplicate grasses cover of high forage value, improving forest condition. We conclude that the actions promoted by the ACVC consolidate it as a key actor in the preservation of the native forest in the area.Fil: Vega, Damián. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Cotroneo, Santiago Miguel. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Mochi, Lucía S.. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Leibovich, Tamara. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: López del Valle, Charo. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Magliano, Patricio Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi". Universidad Nacional de San Luis. Facultad de Ciencias Físico, Matemáticas y Naturales. Instituto de Matemática Aplicada de San Luis "Prof. Ezio Marchi"; ArgentinaFil: Venturelli, Pablo. No especifíca;Fil: Frank, Fernando. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de San Luis. Facultad de Turismo y Urbanismo; ArgentinaFil: Jacobo, Elizabeth Juliana. Universidad de Buenos Aires. Facultad de Agronomía; Argentin

La clausura como estrategia de restauración en bosques heterogéneos comunales del Chaco semiárido. Un enfoque socio-ecológico

RESUMEN: Las clausuras estacionales son utilizadas en África y Sudamérica para diferir forraje a la estación seca y restaurar vegetación en áreas degradadas. En esta tesis se evaluó el potencial de la clausura como estrategia de restauración en bosques de Santiago del Estero, Argentina, mediante dos enfoques complementarios: (a)Ecológico y (b)Socio-ecológico. (a)Se estudiaron los efectos de la clausura en tres bosques con creciente nivel de degradación sobre la vegetación del sotobosque y factores bióticos y abióticos determinantes de su potencial de regeneración, mediante un experimento de 4 años. (b)Se analizó el rol de la clausura en diez comunidades campesinas, mediante un enfoque participativo de sistemas complejos. Se encontró que: (a)La clausura mejoró algunas propiedades físicas del suelo y el banco de semillas. Generó un rápido aumento de cobertura y productividad de gramíneas en bosques, pero no en arbustales, donde la productividad aumentó recién a partir de un ciclo extremadamente húmedo (evento Niño). (b)La degradación responde a interacciones múltiples entre procesos de diferentes dimensiones y escalas. Fueron considerados clave: reducción de superficie de bosque, cambios en composición comunitaria-familiar, demanda de dinero extra-predial y pérdida de diversidad productiva (debidos a la expansión agrícola y las migraciones campo–ciudad). La creciente susceptibilidad del sistema degradado a fluctuaciones climáticas naturales (años secos) exacerba la degradación. La clausura es usada para diversificar usos de la tierra de la finca. Permite estabilizar la provisión de alimentos, bienes e ingresos, ante las fluctuaciones climáticas y de mercado, mejorando así la resiliencia del sistema socio-ecológico.ABSTRACT: Chaco region is the largest extension of land covered by xerophytic vegetation in South America. During the last century, grazing, logging and deforestation have transformed the natural landscape of forests and savannas into a heterogeneous matrix of shrublands and forests in different stages of degradation. The symptoms of this process include less tree cover and herbaceous, bush encroachment, more nude soil, and less water and nutrients availability in the soil, due to less litter contribution, soil compaction and exposition to high temperatures. All these changes reduce the forage production and increase its seasonality, therefore worsening the effect of a marked dry season that lasts 5-7 months over the livestock production. Closures, where grazing is excluded during the rainy season, are used in communal rangelands of Africa and South America, to defer fodder to the dry season and to restore vegetation. Nevertheless, its effectiveness could be conditioned by ecological and socio-ecological factors. The objective of this thesis was to assess the potential of closures as restoring strategy in communal heterogeneous woodlands of semi-arid Chaco region. This was done through two complementary approaches: (a) ecological and (b) socio-ecological. (a) It was assessed the effect of seasonal closures (versus open areas) in three patch types of woodland, with a progressive level of tree canopy degradation (mature forests, secondary forests and shrublands) on the vegetation of the understory and biotic and abiotic factors that determine its regenerative potential. For this purpose, a four-year experiment was done in four sites (true replicates) in different communal woodlands of Santiago del Estero Province (Argentina). The central hypothesis of the experiment was that the higher the degradation status of the woodland the lower the effectiveness of enclosures as restoring strategy because differences in the dominant woody layer would impose differential resource availability in the understory, so controlling vegetation responses to grazing rest. (b) It was developed a theoretical model about factors and processes (ecological, productive, cultural, economic and institutional) associated to degradation. In this context, the role of closures was studied through methodological and theoretical frameworks for complex systems analysis. Perceptions form producers from 10 rural communities and also from technicians (n > 50), were revealed; decision makers who affect directly or indirectly to the system. This data was complemented with field data collection and bibliography. It has been found that: (a) with the rising of the degradation of the tree canopy, the availability of soil nutrients decreased and the incident radiation increased in the understory. The closure generated a quick rise (2 years) of coverage and productivity of grasses in mature forests and secondary forests, but this did not happen in the shrublands. The shrublands might have overcome a certain degradation threshold, related to scarcity of water and/or seeds, which is shown in the lack of grass. In a longer period (3-4 years), the closure improved some physical properties of the soil, which contribute to the infiltration, and increased the grass soil seed bank, in both forests and shrublands, with no grass, that would receive seeds from the former. This would reduce the degradation threshold in the shrublands and would increase the possibility of rehabilitation in extremely (cyclical) humid years, such as in “El Niño” events. These conditions occurred in the fourth year of the experiment, in which a significant increase in grass productivity in the closures of shrublands was generated. That year the coverage of low shrubs reduced significantly in the three patch types of woodland. (b) All the decisive actors interviewed, ascribe degradation to the rising of pressure over the forest, due to the reduction of forest-covered surface and the productive specialization, bound to the agriculture expansion and migration processes. In this context, the closure applies as an adapting strategy, used to re-introduce key species (native, exotic) and to diversify production (agriculture, forestry and livestock). This would offer alternative answers to weather and market fluctuation, and it would stabilize the provision of goods and income, thus avoiding negative emergency practices, such as the excessive production of charcoal for sale. It is concluded that the seasonal closure contains a high potential as restoration tool in heterogeneous woodlands, as well as an adaptive strategy in the adverse socioenvironmental conditions of the semi-arid Chaco. The importance of addressing the subject comprehensively is highlighted, in order to understand the problems of degradation in the search of solutions

Forest degradation and short-term seasonal exclosure effects on biotic and abiotic factors linked to rangeland rehabilitation in semiarid Chaco, Argentina

In semiarid Chaco, wet season grazing exclosures allow a rapid grass recovery in mature and secondary forest patches, but not in the most degraded patches dominated by shrublands. In order to understand the causes of their dissimilar rehabilitation dynamics, we analyzed the effects of the forest-patch type (mature forest = MF, secondary forest = SF, and shrubland = S) and 4-year seasonal exclosures (vs continuous grazing) on biotic and abiotic factors (vegetation structure, incident radiation, grass seed bank, litter and soil traits) that could affect grass recovery. We found that vegetation structure, through determining litter quantity, controlled soil chemical traits. As forest degradation level increased, litter mass (MF = 6260, SF = 5410, S = 1220 kg DM/ha), total soil organic matter (MF = 5.1%, SF = 4.1%, S = 3.5%) and nitrogen (MF = 0.25%, SF = 0.22%, S = 0.18%) decreased, and the incident radiation at soil level rose (MF = 28%, SF = 41%, S = 52%). After 4 years of seasonal grazing rest, we found reduced soil bulk density (from 1.13 to 1.07 and 1.07 to 1 g/cm3) and increased total porosity (from 57 to 60 and 60 to 62%) at 0–10 and 10–30 cm depth, respectively, in all forest patch types. Exclosure also increased soil seed bank density (from 28 to 251 grass seeds/m2) both in the forests (with grass) and in the shrublands (even before grass recovery), which would receive seeds from the adjacent forest patches, which coexist in the same landscape matrix. Our results suggest that the low tree cover, litter, and soil chemical traits related to lower availability of water and nutrient in shrublands, could hamper grass recovery in recently established exclosures. However, improvements in the grass seed bank and soil physical traits related to higher water infiltration could favor its late recovery, which is triggered by an extremely wet cycle after several years of the seasonal exclosure. Exclosure is a promising management strategy for degraded areas involving intermingled patches of forests and shrublands.Fil: Cotroneo, Santiago Miguel. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Jacobo, Elizabeth Juliana. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Brassiolo, Miguel Marcelo. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Forestales; ArgentinaFil: Golluscio, Rodolfo. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Neuroprotective Effects of Citicoline in in Vitro Models of Retinal Neurodegeneration

In recent years, citicoline has been the object of remarkable interest as a possible neuroprotectant. The aim of this study was to investigate if citicoline affected cell survival in primary retinal cultures and if it exerted neuroprotective activity in conditions modeling retinal neurodegeneration. Primary retinal cultures, obtained from rat embryos, were first treated with increasing concentrations of citicoline (up to 1000 µM) and analyzed in terms of apoptosis and caspase activation and characterized by immunocytochemistry to identify neuronal and glial cells. Subsequently, excitotoxic concentration of glutamate or High Glucose-containing cell culture medium (HG) was administered as well-known conditions modeling neurodegeneration. Glutamate or HG treatments were performed in the presence or not of citicoline. Neuronal degeneration was evaluated in terms of apoptosis and loss of synapses. The results showed that citicoline did not cause any damage to the retinal neuroglial population up to 1000 µM. At the concentration of 100 µM, it was able to counteract neuronal cell damage both in glutamate- and HG-treated retinal cultures by decreasing proapoptotic effects and contrasting synapse loss. These data confirm that citicoline can efficiently exert a neuroprotective activity. In addition, the results suggest that primary retinal cultures, under conditions inducing neurodegeneration, may represent a useful system to investigate citicoline neuroprotective mechanisms